#include<stdio.h>
#include<stdlib.h>
typedef struct list* List;
struct list {
    int data;
    List next;
};
int main()
{
    int i, n, flag = 0;
    List s1, s2, s3, t, S1, S2, S3;
    S1 = (List)malloc(sizeof(struct list));
    S2 = (List)malloc(sizeof(struct list));
    S3 = (List)malloc(sizeof(struct list));
    S3->next = NULL;
    s1 = S1;
    s2 = S2;
    s3 = S3;
    while (1) {
        scanf("%d", &n);
        if (n == -1) break;
        t = (List)malloc(sizeof(struct list));
        t->data = n;
        t->next = NULL;
        s1->next = t;
        s1 = s1->next;
    }
    while (1) {
        scanf("%d", &n);
        if (n == -1) break;
        t = (List)malloc(sizeof(struct list));
        t->data = n;
        t->next = NULL;
        s2->next = t;
        s2 = s2->next;
    }
    s1 = S1;
    s2 = S2;
    while (s1->next != NULL && s2->next != NULL) {
        if (s1->next->data == s2->next->data) {
            s3->next = s1->next;
            s1 = s1->next;
            s2 = s2->next;
            s3 = s3->next;
        }
        else if (s1->next->data > s2->next->data) {
            s2 = s2->next;
        }
        else {
            s1 = s1->next;
        }
    }
    s3 = S3;
    if (s3->next == NULL) {
        printf("NULL");
        return 0;
    }
    while (s3->next != NULL) {
        if (!flag) {
            flag = 1;
            printf("%d", s3->next->data);
        }
        else {
            printf(" %d", s3->next->data);
        }
        s3 = s3->next;
    }
}